Homeowners Clinic Expert Q & A - Jan. 2005

The brick chimney in my house projects through the roof surface. I would like some advice on how to install flashing around the joint between the chimney and the roof deck.

BILL WILLIAMS

EAST HARTFORD, CT

Chimney flashing, which is usually made of copper or aluminum, seals the joint between the chimney and the roof. It protects the joint against leakage from rain or melting snow. If constructed properly, it accommodates slight movement between the chimney and the roof.

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Flashing a chimney requires several components. First is the base flashing, which is installed on the lower vertical face of the chimney. It covers the front and wraps around the chimney sides. Then comes the step flashing, which is bent up along the side of the chimney. This is covered by the cap or counter flashing, which is set into the chimney mortar joints and bent over the step flashing. The counter flashing may follow each individual mortar joint and step its way down the side of the chimney, or it may be set into a groove cut in the chimney side called a reglet. The advantage of using the reglet is that it allows a single piece of counter flashing.

Note that the counter flashing also covers the portion of the base flashing that is bent around the corner of the chimney. When movement occurs, the counter-flashing sections slide over the base and step sections without affecting the water-shedding characteristics of the joint.

Over the years I have seen a number of chimneys on which the counter flashing was omitted entirely. Often, in this case, the base sections are sealed with asphalt cement in an attempt to make them watertight. Asphalt cement has a tendency to dry and crack, and requires periodic maintenance. This type of installation is makeshift, and leakage readily occurs along the top edge where the flashing joins the mortar line.

Whenever the width of a chimney located along the slope of a roof is more than 24 in., a cricket (also called a saddle) should be installed at the intersection of the chimney's high side and the roof. The cricket prevents debris, snow and ice from piling up behind the chimney--a condition that can cause rain or melting snow to back up under the shingles and leak into the house. The cricket also deflects water running down the roof around the chimney.

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The cricket's slope should be the same as that of the roof. If the cricket is large and exposed to view, it should be covered with the same shingles as those on the rest of the roof. A small cricket can be covered with metal. The joints between the cricket and chimney, and the cricket and roof, should be flashed.

Rotting Floor Joists

I have a problem with dry rot in the crawlspace under my house. The space is 3 ft. high and there are two vents with a window for access to the space. Can I treat the overhead floor joists with something, or do I have to replace them? Does the space need more air?

S. BABAY

ERIE, PA

If the floor joists have rotted to a point at which they no longer provide adequate structural support, then by all means have them replaced or sistered (that is, fasten another joist to the rotted one's side). Call an engineer or qualified home inspector to make the determination--today. Coating the joists with a surface treatment won't help at all.

It sounds like your crawlspace is excessively damp, which would account for the rotting joists. Does water seep into the area after a heavy rain? Since it's a crawlspace you probably don't go into the area very often, but you need to have a look after a rain. Check the downspouts to make sure they discharge the effluent away from the foundation. Is the ground adjacent to the building sloped away from the foundation or toward it?

Also, does the crawlspace have a dirt floor? An earthen floor is a source of moisture, and it should be covered with a vapor barrier, such as 4-mil polyethylene. Even when the dirt in the crawlspace seems dry and dusty, moisture can accumulate in the area as a result of capillary action. According to the University of Illinois Small Homes Council, as much as 18 gal. of water per day can evaporate into a crawlspace under a 1000-sq.-ft. house.

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The joints of the vapor barrier should be overlapped by a minimum of 6 in., and the perimeter edges should be turned up onto the walls of the crawlspace.

Solder is a surprisingly diverse material. There are separate types for potable water plumbing, automotive coolant tubing, electronic components and architectural sheetmetal. You might find several varieties at the local hardware store or home center, so make sure to choose the right one. Solder for potable water plumbing will either be labeled as leadfree or its label will say, simply, "plumbing solder." Acid-core solder is not intended for potable water plumbing because in most cases it contains lead. It's used for soldering gutters, sheetmetal work and automotive radiators, but not electrical work. To solder electrical components, use rosin core solder. A good source for solder information is the Web site of plumbing products manufacturer Oatey: www.oatey.com.

Preventing Pipes From Freezing

I have a crawlspace under my manufactured home. It's made out of a 4-ft.-high concrete-block wall. I recently replaced the plastic hot- and cold-water lines under the house with 1/2-in. copper lines, which are covered with insulation. I live in an area that can go to minus 20°F in the winter. I heat the house to 68°. Do you think the lines will freeze?

RONNIE KENWORTHY

RENOVO, PA

I can't give you an answer without doing a heat-balance analysis of your crawlspace. I would need to know such things as whether the house's floor and block walls are insulated. Even the thermal resistance (R-value) of the pipe insulation would need to be considered. Some heat from the house will penetrate the crawlspace, but it may not be enough during extremely cold weather.

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To be sure your pipes won't freeze, you can install electrical heating cable around the crawlspace pipes. The cable's temperature automatically adjusts to the appropriate heat output as ambient temperatures change. The cable can be purchased from the LMI Manufacturing Group (www.heattracecables.com.) in prepackaged lengths from 3 to 100 ft. It is available for both plastic and metal pipes. If the pipe's diameter is less than 1 in., it is not necessary to coil the cable around the pipe. The cable can be laid along the pipe and secured with plastic ties. Never wrap heat cable onto itself, as this can start a fire.

MoneySmart Makeovers--Bathrooms is more than just money smart, it's also mechanically smart. It examines a guest bath and a master bath with three different makeovers done to each: economy, midrange and high-end. Clear and crisp color photography follows the action so that you get a close look at tile setting, fixture removal and installation, painting, wallpaper, and electrical and plumbing work. No book can hope to do a watertight job on all those subjects in just 192 pages. Yet this book gets the job done by using step-by-step photography, drawings and concise text. Aside from the basics, excellent tips abound in the book, such as how to neatly install a tile backsplash on a wall that's already painted and finished, how to build a simple wall cabinet using manufactured doors, and how to efficiently tile a countertop. The $20 book is sold at bookstores.

Ventless Heater

Is there a way to control the smell of the exhaust from ventless propane heaters? The heater's supplier doesn't seem to have an answer.

HERBERT R. TRAYLOR

MINFORD, OH

A properly functioning ventless heater will produce a slight odor on firing up. However, once fired there shouldn't be any detectable odor. Your heater should be checked by a qualified service technician. The odor that you are detecting may be caused by dirt buildup in the burners or possibly by improper gas pressure.

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Portable Generator

How practical would it be to use a 2000- to 3000-watt portable power generator to energize one or more individual house circuits during a power outage? For example, could I connect the power outlet of the generator to the electrical circuits for the kitchen and/or lighting fixtures?

MURRAY B. STEPHENS

SAN ANTONIO, TX

A portable generator can be used to power multiple circuits. However, most portable generators will not handle all of the electrical loads at the same time. That usually takes a large, fixed generator. Since most home appliances operate intermittently, a 3000-watt generator can provide adequate power to circuits for the most common appliances, such as furnace, lights, refrigerator, freezer, microwave oven and TV.

There's more to a generator than wattage. You should also examine how easy the generator is to move and service, how easy it is to use and how noisy it is. If your area has frequent power outages, then you need to buy a more expensive and rugged generator, as opposed to one designed for occasional use.

In addition to the generator you will need a transfer switch, which should be installed by an electrician. This switch disconnects the house from the larger power grid and isolates it so that it is served only by the portable generator. The switch also enables the generator to serve the circuits that you have designated to be powered.

The switch is very important because it eliminates the risk of backfeeding the power to the electrical utility, which can cause injury and possibly death to the utility lineman who is correcting the cause of the power outage. The generators and accessories can be purchased at electrical supply stores, home centers and on the Internet.

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Do You Have A Home-Maintenance Or Repair Problem?Just ask Norman about it. Send your questions to Homeowners Clinic, POPULAR MECHANICS, 810 Seventh Ave., New York, NY 10019. While letters cannot be answered individually, problems of general interest will be discussed in the column.

Pipe Dream

Charles Lindbergh flew across the Atlantic in 1927, but that wasn't the big news that year. According to a careful study by the Copper Development Association (the copper industry's trade group), 1927 was also when copper tubing went into widespread use.

With that in mind, the CDA went looking for the oldest, original copper plumbing system still in use. So far it hasn't found a 1927 system, but it did find a house in Fort Wayne, Ind., with an entirely intact system, circa 1937. For more information on copper tubing, visit the CDA's Web site: www.copper.org.

What The Pros Use

Homeowners often consult neighbors and family when they embark on a building project and need to choose materials. They can find out what contractors use by dropping by an online forum hosted by the Journal Of Light Construction. Its Web site, www.jlconline.com, has a monthly survey on everything from hardwood floors to foundation insulation.

Wash And Fold

Maytag's front-loading Neptune washers have become the focus of a class action lawsuit. Maytag has responded that its appliances are not defective. A preliminary notice of settlement says that owners of those appliances manufactured prior to Aug. 9, 2004, may be entitled to repair work, among other redress, if their washer has experienced problems. For information, call 866-288-0515 or visit www.maytagsettlement.com.

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